NTERIOR SEGMENT GLAUCOMA SURGERY
iTrack™ Ab-interno Canaloplasty A Novel MIGS that Reduces IOP and Preserves Tissue by Konstantin Yakimchuk
Glaucoma surgery continues its metamorphosis . . .
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pen-angle glaucoma remains a severe health issue affecting the quality of life of patients and their families. Fortunately, the evolution of surgical methods for the treatment of glaucomatous patients has led to the development of novel minimallyinvasive forms of glaucoma surgery.
The evolution of glaucoma surgeries Currently, the standard surgical treatment for medically resistant openangle glaucoma is trabeculectomy. However, this procedure possesses severe adverse effects to patients, including scar formation, wound leakage, hypotension and detachment of the choroid.1 To confront these complications, canaloplasty — a novel surgical method by circumferential viscodilation and tensioning of Schlemm’s canal — was developed over 10 years ago. Performed via an ab-externo approach, traditional canaloplasty was designed to viscodilate the trabecular meshwork and Schlemm’s canal to repair outflow.2,3 This surgery is recommended for primary openangle and pseudoexfoliative types of glaucoma. Both the decrease and modulation of intraocular pressure are the main current indicators of the surgical treatment efficacy in patients with glaucoma.
canaloplasty, ab-interno canaloplasty or ab-interno canal-based glaucoma surgery, performed with the iTrack™ surgical system (Ellex, Adelaide, Australia), is a new step in the surgical treatment of glaucoma.4 How unique is this novel technique? In contrast to the original canaloplasty, the ab-interno technique does not apply a tensioning suture and requires no conjunctival manipulation. During the ab-interno procedure5, 360-degree catheterization of the Schlemm’s canal is followed by circumferential viscodilation with the injection of a high-molecular weight viscoelastic. The passage of the iTrack™ microcatheter through the Schlemm’s canal mechanically breaks adhesions within the canal and pushes herniations of trabecular meshwork out of collector channel ostia. This restores a more patent architecture to the Schlemm’s canal. Hydraulic pressure caused by injection of HA-based OVD stretches the trabecular meshwork, with possible creation of microperforations into the anterior chamber.This dilates the Schlemm’s canal, ostia and collector channels. The iTrack™ ab-interno canaloplasty reduces IOP by reducing resistance in all segments of the conventional outflow system, including the trabecular meshwork, Schlemm’s canal, and proximal and distal collector channels.
In addition to the original ab-externo
Importantly, iTrack™ ab-interno canaloplasty preserves the angle:
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it does not damage or remove tissue. This is an important distinction of the iTrack™ procedure, as it does not preclude future treatment options. As an added benefit, iTrack™ is one of the few MIGS options that can be performed outside cataract surgery, as a standalone procedure.
Clinical findings in favor of iTrack™ On average, iTrack™ ab-interno canaloplasty achieves a reduction in IOP of 30% and a 50% reduction in medication dependence.6 The procedure has been demonstrated to lower IOP and/or reduce the patient medication burden when performed as a standalone procedure, and in conjunction with cataract surgery.7 It has also demonstrated efficacy in cases of controlled and uncontrolled glaucoma.8 Several studies reporting the application of ab-interno canaloplasty with the iTrack™ surgical system were presented at the American Society of Cataract and Refractive Surgery (ASCRS 2020) Virtual Annual Meeting this year. Among them, a novel study by Dr. Mark Gallardo9 has aimed to evaluate the efficacy and safety of the ab-interno iTrack™ procedure in reducing IOP and glaucoma medications burden in patients with open-angle glaucoma. The author compared the interim
